Oil or grease resistant article.



Ex'mol 9 we; Wa t ISAIAH L. nonnn'rs or Specification of Letters Patent. Patented Sept. 20, 1910.

Application filed Kay 6, 1909. Serial No. 494,464.

4 Qmtow. CKPQBT, NEW YORK.

w re

concern:

Be it known that I, ISAIAH L. ROBERTS, a method applies both to the original pulping citizen of the United States, residing at and to the re-pulping of pulp-board, straw- Lockport, in the county of Niagara and board, etc. In the case of articles made 5 State of New York, have invented certain wholly or in part of re-pulped printed panew and useful Improvements in Oil or per,I have found that the oil of the printers Grease Resistant Articles, of which the fol- 111k is usually sufiicient for the purpose delowing is a full, clear, and exact description. sired; but if not, additional water-repellent This invention relates to articles for exoil or wax may be used.

1 ample tubes, rods, vessels, plates, sheets, etc, From the material treated as above or in composed of fibrous material such as woodany equivalent manner, the vessels or other pulp, strawboard, paper, cotton, and other articles or products are made up into the cellulose products, and has for its object to desired form by the usual methods, and are provide an inexpensive article of the matethen heated. The heating is preferably ef- 1 rial referred to which shall be resistant to fected in a closed or partially closed chamwater, oil or grease, and which shall also her or oven, and is carried to a temperature be non-inflammable. Of the various uses to aboyelhatof boiling water to a pfilttufliwhich articles having these properties may cint to cause the wax or oil to be thorbe put, I may mention in particular the case oughly incorporated with the fibers. The

20 of shipping or storing vessels for containtemperature required for the purpose deing lard or other meat-products, oil, both pends upon the nature of the material and organic and inorganic, and other substances the article, but in no case have I found it of a greasy character. For such purpose necessary to go much above 400 F. and in vessels made according to my invention are many cases a temperature asidw 'as 240 F.

25 specially adapted, being light in weight, has been found sufiicient. The lengtHof efi'ectively resistant to the material which time during which the heating should be they contain, and strong enough to withmaintained also varies, but in general from stand the usage of shipment. two to eighteen hours will be found sufli- In carrying out my invention in the precient. At the lower temperature it is necferred manner I first make a water-repelessary to heat the article longer than at the lent article according to the method set higher temperature; and, similarly, thickforth in my co-pending application Serial walled articles need longer heating at any No. 435,130, filed May 26, 1908, now Patent given temperature than do those whose walls No. 921,001, issued May 11, 1909 which are thinner. In order to be sure of the re- 35 method involves heating the article, prefersults, the heating must be carried on for a ably with the addition of oil, wax, or other period and at a temperature sufficient to water-repellent material in suitable amount. partially decompose the fibers of the article The most important feature of the rocess and effect a combination of the oils, gums described in my said co-pendingapphcation or waxes therewith. At temperatures beresides in the discovery that on heating an tween the boiling point of water and about article composed of fibrous cellulose the 400 F. the heatinghas the effect of strengthfibers of which have some water-repellent ening the articles, but at higher temperatures substance or substances, such as oil or parthey are apt to be weakened. While the use aifin, well distributed on and among them of oil or other water-repellent substance is 45 or naturally in them. in minute or attenubelieved to be necessary for the best results,

ated quantities, so minute in fact as not to I have found that simple heating of articles be palpable to the touch or visible to the made of wood-pulp, etc., will give them waeye, the article will repel water, acting in tor-repellent properties to a marked dethis respect somewhat like the feathers of a gree,suflicient, at least, to serve many purfowl. The treatment with the water-repelposes where substantially waterproof arlent substance or substances can be efi'ected ticles are desired, as for example receptacles in various ways and with various materials, for the storage or shipment of merchandise.

but the organic oils appear to give the best Such articles, made of material of the kind results. For example, in the case of woodreferred to and heated to a temperature of pulp, strawboard, etc., the oil or powdered from 240 to 400 F. for from two to eighteen hours or longer (the higher the p Drawi .2 v Q all w it may wax may be put into the pulping machines and thoroughly mixed with the fibers. This temperature the shorter the time, and vice versa), will maintain their contents dry for along time even under adverse conditions of atmosphere or weather. If water-Va 9;; be added to the atmosphere in the oven in wmirTg'is eifc'feiilhefresifits in some cases wilTbeT'filTproved. For tlii'purpose an open vessel containing a small quantity of water may be placed in the oven or steam may be injected into the latter. The use of water-vapor as described does not result in making the article moist or damp, since the temperature is above the condensing point of water.

A water-repellent article having been made in the manner described above, the next step is to treat the article with a sp lution of sodium or otas sifim sili catijireferably in the manner se orthTIY iny cop e nding application Serial No. 436,650, filed June 4, 1908, now Patent No. 921,002, issued May 11, 1909. The object of this treatment is to impregnate the article with the silicate, the extent of the necessary impregnation being variable within rather wide limits. Thus the impregnation need not be carried farther than well below the surface, or the article may be thoroughly permeated. The .preferred manner of effecting the impregnation is to submerge the article in an aqueous solution of the silicate, the said solution having a specific gravity preferably of from 20 to 25 degrees Baum, though the specific gravity may be somewhat hi her or lower without unsatisfactory resu ts. But when the solution is more dilute than necessary to penetrate the article easily, an excess of water is absorbed which must be got rid of afterward, thus lengthening the subsequent drying of the article. If the strength of the solution is such that the bath is of a thick or viscous character it penetrates slowly and forms small lumps or nodules on the surface of the article when dry. It is better to have the solution hot when used for the reason that the time of submergence is shortened, since the solution is less viscid, and the heat acts in some Way to make the fibers of the article more receptive.

After treatment withathe silicate solution the article is rled, and is then ready for use. I hamd that more satisfactory results are obtained by rapid drying in heated -air, the reason being that'when the article is wet the alkali in the absorbed solution takes up and combines with any carbonic acid gas that comes in contact with it, with the consequent production of carbon ates, which impair the resistant properties of the article and also roduce discoloration.

As previously state the extent to which the impregnation must be carried to make the article satisfactorily resistant, may be varied considerably. In some cases it is desirable not to have the solution permeate the entire article. For exam le, pails, tubs, and other thick and substantia ar icles ned not be impregnated far below the surface, as this makes them sufficiently resistant to water, oi l gr e ase, and fige without adding th'e lififiecessary weight which would result if the article were saturated with the solution. In fact I have found that for waterresistant articles the impregnation should not be much more than a surface treatment, so as to leave an inner unimpregnated core, so to speak. This is for the reason that the silicate is soluble, though of course slowly, in water; and hence 1f the article were wholly permeated the water might eventually make its way through the article by dissolving the silicate. But the unimpregnated core effectually stops the water from penetrating through the article even if the silicate in the surface portions be quite dissolved.

No exact rule can be given for the time of submergence in the silicate treatment, as much depends upon the texture and nature of the article, and also upon the temperature and strength of the solution; but if the 25 i,-Baum, and the temperature of the bath about 180 F., a few minutes submergence wimin' lfily be suflicient for good results. For example, a wood-pul pail, with walls of the usual thickness, wl l he impregnated sufiiciently by one minutes treatment. In any case, however, the time of submergence in the silicate solution, and the specific gravity and temperature of the latter, can readily be determined by trial if necessary.

Articles made as above described will be found admirably adapted for the purposes previously mentioned, for example as shiping or storing vessels for containing oil,

th organic and inorganic, lard, and other substances of a greasy character. At the same time the articles are not only thoroughly resistant to the materials named, but are also light in weight and strong enough to withstand rough usage.

What I claim is:

1. A water and oil or grease-resistant article composed of fibrous cellulose, the article being partially carbonized and impregnated with an alkaline silicate.

2. A water and oil or grease-resistant article composed of fibrous cellulose partially carbonized and impregnated with sodium silicate.

In testimony whereof I afiix my signature in the presence of two subscribing witnesses.

ISAIAH L. ROBERTS.

Witnesses:

M. LAWSON DYER, Sruacns S. DUNHAM. 

